I have two cards who could be by this publisher/photographer. The quality of one is dodgy and the card has faded. I haven't found any reference to this business in any of the directories of the period I've looked at. The card says WYN Lowestoft, but I don't know if "Wyn" is a name or a initials.
I've found another card, with a clear Gwyn, Lowestoft on the back. These could be the same person.